Rework file picker for SSH modal (#19020)

This PR changes the SSH modal design so its more keyboard
navigation-friendly and adds the server nickname feature.

Release Notes:

- N/A

---------

Co-authored-by: Danilo <danilo@zed.dev>
Co-authored-by: Danilo Leal <67129314+danilo-leal@users.noreply.github.com>

crates/gpui/src/window.rs

@@ -4905,6 +4905,12 @@ impl From<(&'static str, usize)> for ElementId {
     }
 }
 
+impl From<(SharedString, usize)> for ElementId {
+    fn from((name, id): (SharedString, usize)) -> Self {
+        ElementId::NamedInteger(name, id)
+    }
+}
+
 impl From<(&'static str, u64)> for ElementId {
     fn from((name, id): (&'static str, u64)) -> Self {
         ElementId::NamedInteger(name.into(), id as usize)